DTC Troubleshooting

DTC P0506: Idle Control System RPM Lower Than Expected

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
4. Check under these DATA LIST parameter conditions with the HDS:

- ECT SENSOR ('04-05 models), ECT SENSOR 1 ('06-08 models) above 158 °F (70 °C)
- IAT SENSOR above 32 °F (0 °C)
- Vehicle speed is 0 mph (0 km/h)
- ST FUEL TRIM between 0.69 and 1.47
- FSS is CLOSED

5. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

Does the screen indicate FAILED?

YES - Go to step 6.

NO - If the screen indicates PASSED, go to step 15. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 4 and recheck.

6. Remove the intake air duct from the throttle body.
7. Check for dirt, carbon, or damage in the throttle bore.

Is there dirt, carbon, or damage in the throttle bore?

YES - If there is dirt or carbon, clean the throttle body. Also check for damage at the air cleaner element, then go to step 9. If there is damage in the throttle bore, go to step 8.

NO - Check the A/C system or power steering system, then go to step 17.

8. Replace the throttle body.
9. Reset the ECM/PCM with the HDS.
10. Do the ECM/PCM idle learn procedure.
11. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.

12. Check under these DATA LIST parameter conditions with the HDS:

- ECT SENSOR ('04-05 models), ECT SENSOR 1 ('06-08 models) above 158 °F (70 °C)
- IAT SENSOR above 32 °F (0 °C)
- Vehicle speed is 0 mph (0 km/h)
- ST FUEL TRIM between 0.69 and 1.47
- FSS is CLOSED

13. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0506 indicated?

YES - Go to step 19.

NO - Go to step 14.

14. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 13, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, go to step 19. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 12 and recheck.

15. Remove the intake air duct from the throttle body.
16. Check for dirt, carbon, or damage in the throttle bore.

Is there dirt, carbon, or damage in the throttle bore?

YES - If there is dirt or carbon, clean the throttle body. Also check for damage to the air cleaner element, then go to step 9. If there is damage in the throttle bore, go to step 8.

NO - Go to step 17.

17. Recheck with different load conditions (turn on the headlights, blower motor, rear window defogger and/or A/C, change the gear position, etc.,).
18. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - Intermittent failure, the system is OK at this time.

NO - If the screen indicates FAILED, check the A/C system and/or power steering system, then go to step 1 and recheck. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 17.

19. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
20. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
21. Check under these DATA LIST parameter conditions with the HDS:

- ECT SENSOR ('04-05 models), ECT SENSOR 1 ('06-08 models) above 156 °F (70 °C)
- IAT SENSOR above 32 °F (0 °C)
- Vehicle speed is 0 mph (0 km/h)
- ST FUEL TRIM between 0.69-1.47
- FSS is CLOSED

22. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0506 indicated?

YES - Check for poor connections or loose terminals at the throttle body and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 20. If the ECM/PCM was substituted, go to step 1.

NO - Go to step 23.

23. Monitor the OBD STATUS for DTC P0506 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCs or DTCs were indicated in step 22, go to the indicated DTC's troubleshooting.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the throttle body and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then go to step 20. If the ECM/PCM was substituted, go to step 1. If the screen indicates EXECUTING, keep idling until a result comes on. If the screen indicates OUT OF CONDITION, go to step 20.